Water quantity: droughts

A drought is a sustained and regionally extensive occurrence of appreciably below-average natural water availability in the form of precipitation, streamflow, or groundwater. Droughts are natural events of varying duration that have occurred throughout history and they are part of the cyclical fluctuations of our planet's climate system.

Droughts can occur anywhere. However, regions with a semi-arid or arid climate, and only marginal annual precipitation to meet their water demands, are more vulnerable to droughts. In Canada, southern Saskatchewan and the interior valleys of British Columbia experience frequent droughts.